1. Field of the Invention
This invention relates to a method and apparatus for conveying bottles and, more particularly, to pneumatically conveying plastic bottles suspended from neck rails while applying retardation forces to the lower portions of the bottles.
2. Description of the Background Art
Many types of plastic bottles are in wide use today throughout the carbonated beverage and other industries, in large part, to their economical cost to manufacture. Such plastic bottles are usually formed from injection molded parisons having threaded upper necks, lower cylinders closed at the bottom, and neck support rings therebetween. The parisons are then blow molded beneath the neck support rings into the desired size and shape by heating the parisons in molds while blowing air internally.
Blow molded plastic bottles have been traditionally shaped with cylindrical side walls throughout the majority of their lower extents and with high-angle, conically-shaped, transition portions between the upper ends of the cylindrical side walls and the neck support rings. The transition portions thus functions to join the upper, small diameter, threaded portions with the lower, large diameter, side wall portions.
Efforts to fabricate plastic bottles in other than such traditional shape have been largely unsuccessful. This is because, when in storage, gasses are released from the liquid of the carbonated contents which results in forces tending to expand the plastic of the bottles outwardly. As a result, any non-traditional shapes molded into plastic bottles become distorted.
Recent developments in plastic bottle technology, developments in materials, bottle design and molding techniques, have resulted in the ability to fabricate structurally sound plastic bottles in a wide variety of complex, non-traditional shapes. Along with the newly found capability of fabricating complex shapes into plastic bottles comes disadvantages. Such disadvantages arise in conveying the plastic bottles through various processing stations of the automated fabrication process.
Specifically, plastic bottles are normally conveyed while suspended by their neck support rings from spaced parallel neck rails. The bottles are conveyed continuously, in a contiguous orientation with the cylindrical side walls of all bottles in a fed stream touching the next adjacent bottles, with each bottle touching the next adjacent bottles at points in the front and in the back and with the bottles touching a control brush along a line. The motive force for conveying is supplied by a high volume, low pressure plenum chamber above the neck rails. The directional force for conveying is supplied through louvers in the plenum chamber walls. Side rails preclude lateral shifting of the bottles while being conveyed. Forward and rearward swinging of the bottles occurs to a limited extent but is not a significant problem with traditionally shaped bottles due to high angle of the conical transition portions between the neck support rings and the upper ends of the cylindrical side walls.
It has been found, however, that conveying problems arise when plastic bottles are fabricated in other than the traditional shape. With the upper threaded portions and neck rings being essentially standard for all plastic bottles, the most severe problems arise when plastic bottles are formed with conical transition portions with low angles, tapers of bottle profile or non-round cross-sectional profiles. Problems also arise when the lower portions beneath the transition portions have a reduced diameter or when the axial dimensions of the transition portions are of reduced lengths.
The most significant conveying problems arise from forward and rearward swinging of non-traditional bottles which causes the neck portions and neck support rings of adjacent bottles to contact, overlap and lock. When this occurs, the portions of the bottles beneath the locked neck rings have their axes fixed in an inverted V-shaped configuration rather than the preferred orientation where the axes of all conveyed bottles are parallel in an essentially vertical direction. Such locking of neck portions and neck support rings invariably results in a misfeed of the bottles being conveyed thereby requiring a shut-down of the system until the neck portions and neck rings are unlocked and the misfeed is corrected, a loss of time and money. Although misfeeds of this type may occur along any region of the feed path of a pneumatic conveyor, they most frequently occur at regions where the bottles are moving around a curve, immediately approaching a curve or immediately following a curve. They also occur at regions where the speed of the conveyed bottles is changed, to faster or to slower.
Pneumatic conveying systems for plastic bottles with neck rings are in wide use today and are described in the patent literature. Note for example, U.S. Pat. Nos. 4,284,370 to Danier and 4,822,214 to Aidlin. No known pneumatic conveying system, however, has the capability to handle plastic bottles with non-traditional shapes without misfeeds arising from neck ring locking.
Accordingly, it is an object of the present invention to provide an apparatus for conveying articles along a path of travel, the articles being of the type having an upper portion for being supported by the apparatus, the articles being of the type having a lower portion for being suspended from the apparatus, the apparatus comprising, in combination, a conveyor defining a path of travel along its length with means for receiving the upper portions of the article to be conveyed; motion imparting means to move the received articles to be conveyed; and retardation means coupled with respect to the conveyor along at least a portion of the path of travel to contact the lower portions of the bottles while being moved for providing a rearwardly directed angle to the articles while being moved to thereby abate the forward and rearward swinging of the articles while being moved.
It is a further object of the invention to provide a method of conveying plastic bottles along a path of travel, the bottles being of the type having a small diameter threaded upper portion, a large diameter lower portion, a low-angle transition portion therebetween, and a neck ring between the upper portion and the transition portion, the method comprising the steps of: providing a conveyor defining a path of travel along its length with means for receiving the upper portions of the bottles to be conveyed; providing motion imparting means to move the received bottles to be conveyed along the path of travel; and retarding the motion of the bottles as they are being conveyed by contacting the lower portions of the bottles for providing a rearwardly directed angle to the articles to thereby abate the forward and rearward swinging of the bottles while being moved.
It is a further object of the invention to convey plastic bottles, having a wide variety of shapes, while suspended by neck rings in a more efficient, reliable and rapid manner.
It is a further object of the invention to abate misfeeds of bottles conveyed by pneumatic conveyors.
It is a further object of the invention to apply a retarding force to the lower portions of bottles being conveyed for thereby eliminating forward and rearward swinging with attendant neck ring locking.
It is a further object of the invention to control bottles to cause them to assume a position for preventing jamming thereof.
It is a further object of the present invention to provide guide rails for retarding a profile bottle from assuming an undesirable position relative to a horizontal axis perpendicular to the direction of bottle path of travel.
It is a further object of the invention to more efficiently handle non-traditionally shaped bottles with low-angle transition portions.
These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other objects and a more comprehensive understanding of the invention may be obtained by referring to the summary of the invention, and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.